RELIABLE DETECTION OF OBJECTS WITH SENSORS FROM COUNTAPUSLE CONTROLS

Countapulse Controls advises that German sensor specialist, Leuze electronic is expanding its portfolio of optoelectronic and inductive switches with capacitive proximity switches.

This move will make it possible for users to procure obtain complete solutions for detection requirements from a single source.

The company has been the official distributor for Leuze electronic for more than 45 years and offers a full technical advisory service. This, Gerry Bryant, managing director of Countapulse Controls, says enables the company to provide fit-for-purpose sensing solutions to industries across southern Africa.

The introduction of contactless, wear-free switches which are resistant to electromagnetic influences, interference and contaminants in the air such as dust by Leuze will have major advantages for end users. The capacitive switches are available in a cylindrical or cubic design, as well as embedded or non-embedded versions for a wide range of mounting options.

Due to their semiconductor technology, the Leuze sensors have a long life expectancy, regardless of the detection and switching frequency.

The new variants facilitate contactless detection of numerous different objects and media, regardless of the shape. These sensors are particularly suitable for detecting objects in harsh and dirty environments due to the IP67 rated housing.

These Leuze sensors can “see through” certain materials, which provides optimum accuracy in difficult sensing applications such as those found in food and beverage and printing and packaging operations. The devices can detect products in outer packaging and behind container walls as well as check fill levels and monitor these for completeness.

Countapulse Controls offers a comprehensive range of sensing, measurement, counting, switching, monitoring and positioning instrumentation solutions. Customer support is through the company’s technical advisory service hotline which is available 24/7.

MENTIS ENGINEERED NON-SLIP FLOOR GRATING GAINS TRACTION

There is a trend away from serrated grating because while it is suitable for some applications, there are others where over an extended period it will no longer provide the underfoot traction required to ensure safety.

Floor grating is never a case of one size fits all, and according to Lance Quinlan, national technical sales consultant at Andrew Mentis, in certain applications the serrated feature on the grating surface becomes filled with grime. “This means that the serrated edge, chosen for this specific feature, no longer functions as a tractive surface and does not provide adequate grip,” he explains.

Andrew Mentis has more than sixty years’ experience producing floor grating at its ISO accredited manufacturing facility and is known as the benchmark product across Africa. Quinlan says it is always important to not only consider the finish of the floor grating selected for an application, but also critical to look at how the grating is being manufactured.

Mentis Flat Top floor grating is manufactured from slit coil material which provides the major advantage of having the flat top finish for which this product is named.
This is unlike other manufacturers in the industry where the top of the flat bar has a rounded finish due to the manufacturing process at the mills. The disadvantage of the rounded top is that it will give little to no grip underfoot.

In addition to its Mentis RS40 (40/40) floor grating which is considered the benchmark product across a range of industry sectors, Andrew Mentis, long ahead of the curve when it comes to providing solutions in floor grating, has also engineered a specific floor grating product that has a unique positive/raised non-slip characteristic on the flat bar section.

“While we do offer the serrated top if requested, we prefer to supply positive non-slip to our customers,” says Quinlan. “By serrating the bar the strength of the grating can be reduced by up to 25%. We see that as an uneconomical use of steel which does not translate into value for our customers.”

By manufacturing the flat bar section with this unique raised dimple feature, Andrew Mentis has provided a grating which offers a far better tractive surface than just the plain Mentis flat bar grating and the Mentis serrated grating, while retaining the same strength as the flat top product.

Mentis Rectagrid RS40 (40/40) Non-Slip grating is available ex stock in panel sizes of 2400 mm by 1200 mm. And importantly, for customers who have specific application requirements the floor grating can be tailored to meet the specific drawing requirements.
It is also available in mild steel unpainted, bitumen painted and galvanised.

This highly engineered floor grating product is produced at Andrew Mentis’ world class facility at Elandsfontein, Johannesburg.
The company offers a full technical advisory service to assist to customers in the selection process, and Quinlan says this service has become increasingly popular with industry.

RAUBEX INFRA PAVES THE ROCKY ROAD TO SOFT LIVING

Work is well underway to open a second phase – Bergendal – at Bloemfontein’s sought-after Woodland Hills Wildlife Estate residential development.
Raubex Infra’s civils division is currently putting vital infrastructure such as storm water pipes, water reticulation, sewers and streets in place.

According to Raubex Infra site agent, Jaco de Jager, the work will make way for another 84 properties of 1,000 m2 each and includes the upgrading of an access road from the provincial R700 route nearby to the Bergendal Gate as well as some enhancement to the R700 itself.
On the Woodland Hills site, work is underway to complete 21,000 m3 of mass earthworks, 22,000 m3 of layer works, and 6,300 m3 of trench excavation.

“The rocky surface conditions in the area required us to conduct extensive blasting in the early months of the contract, to ensure that pipes could be laid to the correct depth,” says de Jager.

The work also includes excavations for slabs and drainage, and about 33,000 m2 of asphalt surfacing will be laid.

In line with the development’s environmental priorities and growing concerns about South Africa’s water scarcity, Raubex Infra will also be installing a grey water line from the nearby sewer station.
This water source will be used for irrigation purposes and will reduce the estate’s environmental footprint while helping ease pressure on the municipality’s treated water capacity.

Another initiative has been to make full use of the blasted surface rock. This is broken further by excavator-mounted hydraulic breakers before being fed into the on-site crushing plant for G2 aggregate production.

“We use the minus 75 material as backfill for the pipe trenches, and also supply a minus 200 fraction which will be used during construction of the development’s dam wall,” he says. “We are also using selected stone to create a G2 material that is used for the road base.”

The low-traffic roads on the estate are constructed with three layers, a selected layer, an upper selected layer and premix asphalt on the surface.
Instead of creating the base on the road using a grader and water bowser, the material is mixed in an on-site pug mill supplied by Raubex Infra’s plant division.

“The pug mill efficiently creates the mix with the required 8% moisture content, eliminating the need for conventional water spraying on the road,” de Jager says. “It also pre-mixes G1 material for our enhancement work on the high-traffic R700 provincial road.”

To ensure that stormwater is adequately channelled from the new development’s access road, there are barrier kerbs with purpose-designed kerb inlets.
Precast items for the inlets are being cast on site by Raubex Infra. To ensure the effectiveness of the storm water system, a 300 mm concrete channel will carry water away and prevent ingress.

The access road is built to a robust design given the water-flow conditions in this hilly area.
The minus 200 fraction pioneer rock layer is followed by a selected layer, upper selected layer, sub-base and base with pre-mix asphalt on the surface.

Leveraging the power of technology, a global positioning system (GPS) on site allows the two full-time surveyors to set out points and levels, constantly monitoring the accuracy with which the plans are implemented.

Having begun work in October last year, Raubex Infra’s contract at Woodland Hills is due for completion in the third quarter of 2018.

WEIR MINERALS AFRICA SHOWCASES END-TO-END SOLUTIONS

Visitors to this year’s Electra Mining Africa exhibition at Nasrec will be in for a feast of technology at the Weir Minerals Africa stand; particularly hard to miss will be their 7 metre high crushing station featuring a high performance Trio® cone crusher.

“We are reminding visitors and customers that Weir Minerals Africa – well known for our pump technology – has transformed into an integrated solutions provider in minerals processing,” says Hoosen Essack, Process Manager at Weir Minerals Africa.

“With our extensive footprint across Africa, we are adding even more value through this growing range of offerings.
Underpinning our service levels is our process expertise that equips us to partner closely with customers in finding answers to their daily challenges.”

Among the other items on display will be a large Cavex® hydrocyclone with a substantial 1500 mm diameter and weighing five tonnes.

With the company’s leading position in pumping equipment, the stand will also display the impressive Waman® 450MCR pump, measuring 2,5 metres in diameter.

Essack highlights the strategic importance of the company’s process department, which is staffed with experts who work closely with customers on efficiency and other issues, whether on a particular item of equipment or an entire comminution circuit.

“This capacity allows us to provide enhanced support to customers on their plants, taking our role well beyond just supplying product,” he says. “This centralised team of experts are available to all of our branches, so customers can always be assured of skilled input on challenging problems and equipment choices.”

He emphasises the value of specialised tools employed by Weir Minerals, such as the JKSimMet software to simulate comminution and classification circuits, in helping customers select the appropriate solutions for their mineral processing plants.

“To consolidate our continuous improvement efforts and stay at the leading edge of technology development, research and development is a strong focus for Weir Minerals,” he says. “Weir Minerals as a leading global player also has centres of excellence around the world to each focus on each particular field.
While South Africa focuses on screen performance, for instance, the United States focuses on comminution equipment and centrifugal pumps.”

HOW BOOYCO USE OF VLF TECHNOLOGY MAKES MINES SAFER

The application of very low frequency (VLF) technology in the development of underground safety equipment has been an important step towards achieving the mining sector’s objective of zero harm, according to Booyco Electronics engineer and developer Frank Schommer.

Booyco Electronics began developing collision warning systems over a dozen years ago, using VLF technology to build a proximity detection system (PDS) for underground mines and becoming a pioneer in this complex field. VLF, says Schommer, is used to generate a magnetic field – based on low frequency technology – around a vehicle, essentially an electric ‘fence’ which is independent of the material present in the immediate environment.

“In other words, VLF technology allows this magnetic field to travel through obstacles like rock and water, maintaining the ‘fence’ at a constant distance from the vehicle,” he says. “This means that the shape of the fence around the vehicle remains exactly the same, whether the vehicle is underground or on surface.”

He notes that the physics of VLF is a well-established area of science and industry and was an important aspect of submarine evolution as it allowed these craft to communicate while submerged as VLF waves can penetrate though water.

“Due to their frequency, the waves are not reflected by walls or other elements of the environment, rather they penetrate these objects,” he says. “This allows our PDS to create this invisible fence around mining vehicles at a certain pre-set distance, depending on the specific application and the customers’ requirements.”

What is vital is that the corners and crossings in an underground haulage will not affect the shape and size of the magnetic field around the vehicle as the waves will penetrate the rock walls and other obstructions that limit what operators and pedestrians can see.

“If the pedestrian is behind another vehicle, for example, or behind a corner in the tunnel, the proximity detection system must be able to pick up and pinpoint their position – and this is what VLF allows us to accomplish so effectively with our PDS solution,” he says.

He describes how the principle of VLF is easily recognisable in daily life, in the case of sound waves from a radio or music playing device. When listening at a distance, it is usually the bass sounds that reach the ear more readily, while the treble sounds – those carried by higher frequency waves – are not; this is because the high frequency waves will be reflected by walls and other objects, so will not travel far.

Surround-sound systems also demonstrate the principle: while there are a number of smaller, higher frequency speakers situated around a room to give the listener the sensation of sound coming from different sources, the system provides only one bass speaker.
This is because the behaviour of the lower frequency waves makes it more difficult to sense the direction of their source.

He notes that, despite the advantageous characteristics of VLF waves, it is still a challenging process to actually create a magnetic field to the exacting specifications demanded by safety applications.
It requires high levels of power in the transmission antenna to generate the field, for instance, and even in the receiver as well.

He emphasises that PDS, when applied in the sphere of worker safety underground, must ensure absolute stability of conditions so that the performance of the technology can always be relied upon to operate optimally and be fit-for-purpose.

“That is the reason why we have used VLF technology as a basis for our solutions,” he says, “as these waves are best able to deal with the reflective environment in underground workings and maintain fields of a constant size or distance from the source.”

Booyco Electronics’ market-leading innovations have leveraged VLF technology to provide valuable functionality for mine safety initiatives; among the most important of these is the creation of detection ‘zones’ within the magnetic field which trigger specific greater operator warnings and subsequent actions.

“Our technology allows us to define the accuracy of these zones to within very low deviation tolerances,” says Schommer. “For instance, our first zone of safety may be 20 metres from the moving vehicle – and this is accurate to within 10 centimetres.”

When a miner – equipped with a VLF receiver and buzzer unit – enters this zone, the system sends a warning through a flashing light and buzzing sound, to alert them to the fact that they are entering a dangerous area.
Importantly, the behaviour of the VLF waves will allow the miner to be alerted even if they are behind a corner or otherwise out of sight of the vehicle operator, when within the detection range.

A second zone, closer to the vehicle, is also set up in the PDS to warn the vehicle operator that there is a pedestrian in the proximity.
If the pedestrian does not respond to the warnings and gets even closer, they will enter a third zone which could now trigger the mechanical intervention: switching the vehicle automatically to ‘creep’ mode.

Should the pedestrian enter the last zone defined by the PDS – even closer to the vehicle – then a second intervention comes into play, stopping the machine in its tracks to avoid any possible collision or injury.

CHRYSO SOLUTIONS FOR EVERY READYMIX NEED

The readymix sector faces a plethora of different demands daily for concrete applications, and CHRYSO Southern Africa has the solutions to ensure that every delivery meets the customer’s requirements.

Common issues such as durability of concrete due to shrinkage cracking can be addressed by CHRYSO products that reduce early and long term drying shrinkage, while the CHRYSO™ Fluid Optima range combats the effect that shrinkage-reduced admixture may have on the strength of the concrete.

Pumping concrete over long horizontal or vertical distances brings the danger of concrete stiffening in the line which can disrupt the pumping operation. CHRYSO’s product ranges can modify concrete rheology to provide the required lubrication within the pump line, reducing pump pressures and improved concrete flowability and providing better workability retention for long pumping distances.

For concrete mortars, CHRYSO admixtures can improve plasticity, cohesion and adherence, and prevent infiltration of water, plastic shrinkage cracking, and the segregation of fine cement and sand particles. Shotcreting is another common application that can be enhanced by the right concrete; available solutions include fibres for cohesive mix to limit rebound and shotcrete accelerators to improve build-up.

Fibre reinforced concrete is ideal for limiting the formation of cracks and for improving surface quality; it can even provide an alternative to mesh reinforcement. Superplasticisers are part of the offering, as fibres tend to reduce the workability of fresh concrete.

Impermeable concrete for waterproof or underwater applications can be achieved by CHRYSO products that reduce water content and water-cement ratios, as well as admixtures that block pores in concrete. In situations where vibration is not possible to compact concrete, self-compacting concrete is the answer and the correct CHRYSO product will allow high fluidity, ease of placing and finishing, with extended slump retention if required

CHRYSO’s extensive range of solutions is based on leading-edge R&D, and can be produced in 26 facilities worldwide, each equipped with sophisticated technology for precision manufacturing.

MBE MINERALS TO ENGAGE VISITORS AT ELECTRA MINING AFRICA

MBE Minerals will showcase its product and service offering at Electra Mining Africa 2018, and managing director, Johannes Kottmann, says this will provide an opportunity for existing and new customers to engage with the company’s technical team.

Kottmann says that among the technologies that is seeing increasing demand is the BATAC® jig. The main advantage of this innovative technology is the excellent separation accuracy it offers as well as its relatively small footprint.

“Available at a comparatively low capital cost, this field proven technology delivers higher throughput rates and efficiencies,” he says. “Add to this improved product quality and you begin to understand why it is acknowledged as offering significant economic benefits.”

The company’s ROMJIG® has also proven to be a reliable and economical solution in destoning raw coal. Kottmann says a lower percentage of refuse in the washery feed means reduced wear on machinery and transporting equipment, less grain degradation, less dust and slurry and reduced consumption of flocculation and flotation agents in downstream fines recovery circuits.

Another technology that has attracted global attention is the Pneuflot® flotation technology which Kottmann describes as the flotation technology of the future.

“There are 82 Pneuflot® installations in coal globally and in magnetite and haematite (itabirite) flotation,” he says.

The Pneuflot® flotation cell improves efficiency as well as product quality and recovery, delivering lower capital and operating costs. Its unique design, with no rotating parts, achieves low energy consumption and less wear-and-tear than conventional agitator cells.

The Jones® Wet High Intensity Magnetic Separator (WHIMS) offers a high throughput capability coupled with simple maintenance and lower energy consumption. The robust WHIMS, operated at up to 14 500 Gaus, is ideally suited to treating feebly magnetic minerals with a particle range from 20 microns up to 1.5 mm with unit throughput capacities from 500 kg/h up to 250 tph.

The largest WHIMS plant in the world, outside of Brazil, was installed in the Northern Cape by MBE Minerals SA.

Also available from MBE Minerals SA is the Palla Mill® which is suitable for both wet and dry applications in primary and secondary grinding and for pulverising materials of any hardness. It has a major advantage over other machines as it is capable of grinding more than 100 different materials, including a range of minerals and commodities previously considered unviable due to the costs involved.

MBE Minerals SA also manufactures a variety of vibrating screens, available up to 3.6 m in width and 6.75 m in length, in single or double deck configuration and in either circular or linear motion. The company’s screens have been operating in the African mining industry for the past 40 years, mainly in the coal, diamond and iron ore sectors.

With products for sizing, scalping, dewatering and media recovery, the company’s screens feature an innovative side plate mounted drive, making them lighter than those using vibrator motors. MBE Minerals SA also supplies screens with vibrator motors where required, while its resonance screens offer the benefit of low power consumption. Each screen is designed with sound mechanical features including vibration damping, side plates, cross members and the appropriate feed and discharge chutes. All types of screening surfaces can be accommodated.

AGILITY KEEPS CONCOR INFRASTRUCTURE PROJECT ON TRACK

The South African National Roads Agency SOC Limited (SANRAL) project on the N2, between Mtunzini and Empangeni in KwaZulu-Natal, has brought with it its own challenges and in so doing has allowed Concor Infrastructure to demonstrate its agility as one of South Africa’s leading roads contractors.

The project, which includes substantial works such as the building of 11 bridges, comprises the construction of a new northbound carriageway and the rehabilitation of the existing road to form the future southbound carriageway on this 34 km section of the N2.

Jonathan Pearce, Concor Infrastructure’s contracts manager on this project, says that while it is certainly not unusual to fine tune the construction programme on a major roads project such as this, the level of adaptability and flexibility required on an almost daily basis bears testimony to the company’s reputation for delivering on complex roads and infrastructure projects.

“Detailed planning forms the basis of all successful projects, however the high level of agility required on this project places it in a category of its own,” he says. Significantly, agility is one of Concor’s intrinsic values together with teamwork, care, trust and delivery.

Among the challenges experienced since the contract start in March 2016 has been the unpredictable tropical climate of the region with some weather events causing significant damage to works with consequential delays. Geotechnical difficulties were also experienced during piling activities on some of the critical bridges leading to delays to the construction programme for these structures.

Pearce says that the project remains on track and this is largely due to the team’s ability to adapt the sequencing to accommodate the various challenges as these have been confronted on site. “Not only is it about having a quick and appropriate reaction to situations as these arise, but it is also about having the necessary in-depth technical knowledge and practical experience as well as the necessary resources to minimise the impact of the consequential delays.”

A critical requirement of all major roads projects today is the up skilling of SMMEs from within the local communities. It is critical to be able to identify those individual enterprises that have the requisite basic knowledge and skills sets required for a particular task, and then to develop, mentor and grow these small businesses to become sustainable in their own right.

“In many instances, the learning curve for these SMMEs has been massive and it has required the construction programme to have the in-built flexibility to change at short notice to accommodate issues with the works packages where SMMEs are involved,” he says.

Careful planning applied to these areas of work which have included sub-soil drains, pipe culverts and head and wing walls has allowed the impact to be minimised wherever possible, while still ensuring that the quality of workmanship meets the high standards that Concor Infrastructure imposes on itself and its subcontractors.

An example where an SMME has contributed positively to the project is the construction of the v-drains which is being done using slip forming. The mechanisation of this task has ensured consistent quality and eliminated wastage, saving both on time and cost.

Commenting on the status, Pearce says that the road works have progressed to the point where most of the earthworks have been done as well as a significant portion of the layer works.

Asphalt work is also underway. The project will consume around 220 000 tonnes of asphalt and Concor Infrastructure established its own Comar asphalt batching plant on site, resulting in additional time and cost savings.

Of the 11 bridges, three are at a point where desk construction is underway and on the remaining eight only parapet work is still to be done. The two largest bridges are road over river structures with the eight span uMhlathuze River bridge being the longest at 240 metres while the uMlalazi River Bridge is 120 metres long. The former is at 75% completion while the latter is 90% complete. The extension of all four overpass bridges has been completed and Empangeni interchange bridge is almost finished.

INSERT BOX
Concor Infrastructure achieved the massive milestone of 2 million Lost Time Injury Free (LTIF) hours on the Mtunzini project. What is particularly significant is that the work is conducted on numerous faces on this complex construction project with a vast array of engineering facets being employed.

“Safety is an important focus at Concor, and the achievement on this site shows that the objective of zero-harm is within reach,” Pearce says. “Attention is given to ongoing skills development and training to ensure that all stakeholders, not just the Concor people, understand the safety requirements that have enabled us to reach this milestone.”

The site follows a stringent safety protocol on all its activities, which is underpinned by Concor’s Visible Felt Leadership approach.

INTEGRATED PUMP TECHNOLOGY SHOWCASES PUMP RANGES

Integrated Pump Technology will showcase its range of global OEM pumps at Electra Mining Africa.
The company was established four years ago as the official southern African distributor for the well-respected Grindex range of electrical submersible pumps and last year introduced the Italian manufactured Faggiolati pumps to its product offering.

Grindex pumps incorporate a unique air valve that allows the impeller to pass air instead of water protecting the unit in dry run conditions. These robustly constructed pumps are engineered to operate in harsh environments offering end-users reliability and energy efficiency.

The range of Grindex dewatering pumps range in sizes from 0.5 kW to 90 kW with a new 145 kW unit currently in field trials. This unit will be released to market early next year.

The Grindex slurry pumps are robust workhorses made for use in mines and quarries and sizes range from 3 kW to 70 kW. These pumps are equipped with an agitator mechanism that directs settled material to the pump’s intake.

The sludge pump range has all the advantages of the other two ranges as well as a recessed vortex impeller and split hydraulics with replaceable rubber linings. This allows these pumps to handle larger solids with increased abrasion resistance.

Manufactured in Italy, the Faggiolati quality submersible drainage and wastewater pumps are considered a natural complement to the company’s Grindex pump and accessory range.
One of the most significant advantages that Faggiolati pumps offer is that all units are equipped with Premium Efficiency IE3 motors. This is particularly important on a continent that needs energy efficient products and solutions.
The extensive product line-up, more than 800 items, ranges from 0.5kW to 350 kW and pumps are available in grey cast iron as well as marine bronze and stainless steel for specialised applications.

Integrated Pump Technology has a strong network of 16 strategically located distributors each of which has a solid track record.
This facilitates rapid local access to sales and technical information with the distributors being supported by dedicated account managers ensuring effective and optimal solution providing and service.

SAFETY AND FIRE SOLUTION COMPANY CHOOSES APEX STRIP CURTAINS

It makes sense that Firebreak SA, a company focused on providing quality safety and fire solutions to industry, would select Apex General Purpose Strip Curtains to cordon off its receiving and despatch area at its facility in Alrode, Johannesburg.

Apex General Purpose Strip Curtains are manufactured from specially formulated PVC material which can withstand the movement of both pedestrians and motorised materials handling equipment without snagging or scratching.
The ends of the individual strip are reinforced by the patented Balledge® which when closed allows an efficient seal preventing unwanted contaminants from entering the cordoned off area.

Receiving and despatch areas are often a hub of activity with products being received from suppliers, and others being despatched to customers daily

Wim Dessing Jnr, sales director at Apex Strip Curtains & Doors, says that it is not uncommon for companies to want to control the ingress of dust and foreign particles at such facilities, especially delivery vehicles moving in and out most of the working day creating excessive dust.

“There was, however, an additional need at Firebreak SA, and this was to supply a solution that would allow the entrance to be opened completely, when necessary,” Dessing says.

This was accomplished by installing the Apex General Purpose Strip Curtains on a sliding rail in the opening.
The specially designed track allows the strip curtaining installation to be opened to allow vehicles to access the area, and then closed once the vehicle has left.

Dessing Jnr says the company has been supplying fit-for-purpose products for door openings in industrial and retail facilities for more than 40 years and works closely with customers to find appropriate solutions. Apex Strip Curtains & Doors supplies general purpose strip curtains, high impact traffic doors and high speed roll-up doors.